SDL_mixer: docs: Make threadsafety text for MIX_UnlockMixer match SDL_UnlockMutex().

SDL Commits
1 
From 81e68a9da84673001aceec8af731b6c649af7830 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Thu, 5 Mar 2026 10:05:59 -0500
Subject: [PATCH] docs: Make threadsafety text for MIX_UnlockMixer match
 SDL_UnlockMutex().

---
 include/SDL3_mixer/SDL_mixer.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/SDL3_mixer/SDL_mixer.h b/include/SDL3_mixer/SDL_mixer.h
index de347ec0..e10d5f42 100644
--- a/include/SDL3_mixer/SDL_mixer.h
+++ b/include/SDL3_mixer/SDL_mixer.h
@@ -580,7 +580,7 @@ extern SDL_DECLSPEC void SDLCALL MIX_LockMixer(MIX_Mixer *mixer);
  *
  * \param mixer the mixer to unlock. May be NULL.
  *
- * \threadsafety It is safe to call this function from any thread.
+ * \threadsafety This call must be paired with a previous MIX_LockMixer call on the same thread.
  *
  * \since This function is available since SDL_mixer 3.0.0.
  *